What Is an Eclipse?

An eclipse occurs when one astronomical object such as a moon or planet moves into the shadow of another one. 

There are two types of eclipses that can be observed from Earth: lunar and solar. 

What is a solar eclipse? 

The Moon orbits around the Earth and sometimes the Moon is between the Sun and Earth. When this happens, the Moon blocks the light of the Sun from reaching Earth, causing a solar eclipse.         

During a solar eclipse, the Moon casts a shadow onto Earth.

There are three main types of solar eclipses:

• Total solar eclipse: A total solar eclipse is visible from a small area on Earth. The sky becomes very dark, as if it were night. For a total eclipse to occur, the Sun, Moon and Earth must be in a direct line.
• Partial solar eclipse: This happens when the Sun, Moon and Earth are not exactly aligned. The Sun appears to have a dark shadow on a small part of its surface.
• Annular solar eclipse: An annular eclipse happens when the Moon is farthest from Earth. Because the Moon is farther away, it seems smaller and it does not block the entire view of the Sun, creating a ring around the Moon.

Content provided by the Baylor University Department of Physics. To learn more about the department, visit their website at baylor.edu/physics.